LED lamp consisting of light emitting diodes (LED) with circadian adjustable mode of radiated light providing for its health safety

ABSTRACT

The invention application deals with the LED light having at least two simply switchable lighting modes. The first mode quite eliminates the blue wavelength light which is harmful to human organism at night. It&#39;s recommended to always turn this light on after nine in the evening and use it until the sunrise. The second mode already has a low blue wavelength content, being suitable during afternoon hours and relaxation. The third mode already represents the daily sunlight with a high CRI value and should be used during day only. The mode switching is set in a way that after turning the light off and then on again, the first mode with monochromatic red colour will light first, thus the circadian rhythms are not affected at each wakeup and turning on the light.

FIELD OF APPLICATION

LED lamps with variable selection of light level and possibleelimination of blue wavelengths according to modes to day and night.

STATE OF THE ART

More than 130 years ago, people were going to bed after the sunsetwithout being affected by any artificial lighting. However, with theinvention of bulb, the bed time shifted with the day being forciblyprolonged, leading to insomnia rise in a large number of people.

The first bulbs' filaments were formed by charred bamboo strings orthreads giving light equal to fire light, i.e. red monochromatic lightwithout the blue wavelength. Later on, tungsten began to be used as themost suitable material and it's still used to date. Light emitted by atungsten source already contains the blue wavelength. LED sources arethe latest ones which use a blue LED to emit light in the shorterwavelength spectrum or create the white light using RGB chips, i.e. bymixing three basic colors. In addition to the light sources, LED TVsets, mobile phones, tablets etc. appeared progressively in the market.They emit blue light in the eyes all day, even after the sunset.

However, we don't feet the arising issue consciously, but this isperceived by the photosensitive retinal ganglion cells. These cellsinfluence the circadian rhythm that tells our body what time it is. Thekey role in synchronizing our internal biological clock is played byhormone melatonin whose creation is conditioned by full darkness. Inaddition to the sleep control, melatonin has preventive effects againstcancer, slowing down aging and helping to prevent Alzheimer's orParkinson's disease. Our melatonin levels are reduced during night workshifts or for example if we wake up in the middle of night and turn on ablue wavelength light. The boundary which does not influence themelatonin level is above 600 nm which is the red color wavelength. Thus,

light sources with a high blue color proportion with a wavelength around460 nm should not occur at night, they just might be present in suchrooms where human attention needs to be kept, such as in operatingtheaters, flight operations etc. One does not need a daylightreplacement or exact color recognition at night, one just needs to seewhich can be fulfilled enough by reddish light color. The solution couldbe in using electronic devices with red glasses or a red filter appliedafter 21 o'clock. So far, either fire or a tungsten filament bulb dimmedwith a dimmer was a suitable light source to be used after 21 o'clock ina household. (MEDŘICKÝ, Hynek. Light and its impact on human body.Light. 2015, 2015(6), 53-57.)

Today, more than 60 percent of the population live in environment withnight light pollution. The illumination levels in urbanized areastypically reach levels around 20-80 lux, however, even values exceeding100 lux are no exception which is a thousand fold of the full moon'slight intensity. The high ratio of the blue spectrum color may have anegative impact on the human sleep quality in neighboring objects oreven on the life cycles of animals, mainly the birds. Human organismfalsely perceives light as a day signal in the middle of night,triggering biochemical processes to secure its daily activity, thussupporting its exhaustion (Burnett D. (2015) First do not harm:Practicing lighting design or medicine . . . without licence? Lecture at6th Velux symposium, London).

Light pollution is easy to find at a glance when we look up to the skyand we cannot see the stars. The more blue wavelength, the more lightpollution. Currently, there are few people using low pressure sodiumlamps (LPS) but these have faded away after entry of LED lamps. Theselamps do not provide any blue wavelength, they emit just monochromaticamber-yellow light, and thus they have the least environmental impactand least affect circadian rhythms. They are utilised in astronomicalobservatories and for nesting of sea turtles. Narrow-band amber LEDextends the orange-yellow wavelengths with the green one and they arenot so safe. So called PC amber LED covers all the green wavelengthrange. In municipality Santa Pau in Garrotxa Region, street LED lampshave been replaced with PC amber LED lamps, and the latter partlyeliminate the blue wavelength, the light is then much more pleasant inthe evening but the blue wavelengths are not eliminated completely.Another LED type is a filtered warm white LED—straw yellow LED lamp witha filter that removes most emission with wavelength below 500nanometres. Another type of a LED, which is almost

neglected, is a warm-white LED with chromaticity temperature of 2700 K.The most frequently used LED is a cold LED with chromaticity temperatureabout 5000 K or 4000 K. This source of light that covers all thespectrum is misused in household and in street lighting day and night.(A comparison of the representatives of lamps and their spectra ispresented in FIG. 1)(http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-light-pollution/).

The LED activity principle is based on radiating energy in form ofphotons while electric current is passing through a semiconductorjunction formed by semiconductor material, typically GaN or InGaN.Overview of application of semiconductors in current colour LEDs:

Infrared—λ>760 nm, gallium arsenide (GaAs), aluminium gallium arsenide(AlGaAs) Red—610<λ<760 nm, aluminium gallium arsenide (AlGaAs), galliumarsenide phosphide (GaAsP), aluminium gallium indium phosphide(AlGaInP), gallium phosphide (GaP).

Amber—590<λ<610 nm, gallium arsenide phosphide (GaAsP), aluminiumgallium indium phosphide (AlGaInP), gallium phosphide (GaP)

Yellow—570<λ<590 nm, gallium arsenide phosphide (GaAsP), aluminiumgallium indium phosphide (AlGaInP), gallium phosphide (GaP)

Green—500<λ<570 nm, aluminium gallium indium phosphide (AlGaInP),gallium phosphide (GaP), aluminium gallium (AlGa), aluminium phosphide(AlP)

Blue—450<λ<500 nm, zinc selenide (ZnSe), indium gallium nitride (InGaN),siliconcarbide (SiC)

Violet—450<λ<500 nm, indium gallium nitride (InGaN)

Ultraviolet—λ<400 nm, aluminium nitride (AlN), aluminium gallium nitride(AlGaN), aluminium gallium indium nitride (AlGaInN)

Any LED emits colour spectrum according to the applied semiconductor.LEDs, however, cannot emit white light because white light is a mixtureof all colours. Photoluminescence is used to produce white light.Luminescence occurs when an atom is excited through action of otherradiation, electrons and the like, and then the atom returns in itsground state and a photon is emitted. The substances where theluminescence occurs are called luminophores. LEDs are fitted with a thinlayer of luminophore embedded in a silicone mixture, it is favourable touse a mixture of several different luminophores according to therequired resulting colour spectrum.

The most important LED properties are these: chromaticity temperatureand colour rendering index. Chromaticity temperature is given in kelvinsand it represents the colour rendering of light. The more kelvins a Ledhas, the more the artificial light resembles day sun light. Classicbulbs have this value around 3000 K, white cold LED has about 5000 Kwhich is close to day bright light. Chromaticity temperature ofhousehold lamps should differ according to their application (higherchromaticity temperature in kitchen than in bedroom).

Another important property is the colour rendering index (CRI) whichdetermines ability of a light source to reproduce colours of anilluminated object when compared with natural sunlight. The ideal valueis 100 which corresponds to the day sunlight, most frequently used LEDlamps have CRI about 80. The above mentioned sodium lamps have zerocolour rendering (CRI=0) and thus this lamp is not advised to use

e.g. during winter when the dark comes at 5 p.m. but we still need towork and to distinguish colours. White light without using luminophoresis used through a so called RGB LED where blue, green and red chips areswitched together. The colour rendering index is, however, rather bad,it is about CRI=24.

The key function of melatonin in a man is regulation of the circadianregime of an organism. Melatonin is therefore primarily a chrono-bioticsubstance (Illnerová, H. 2008). If we spend a day in a cyclic manner, wehave the day divided, without always realising this precisely, into asubjective day and a subjective night. When our subjective night isapproaching, we begin to feel sleepy. Hormone melatonin starts to createin epiphysis situated in brain and it starts to discharge in blood.“Melatonin expands vessels in our limbs, our warm escapes in environmentand body temperature drops. Generation of melatonin drops or stopscompletely early in the morning and temperature rises. Also generationand release of hormone cortisol from adrenal glandsrises” (FIG. 26)(Illnerová, H. 2005, p. 9). It is a hormone which is discharged understress the task of which is to pre-prepare us to troubles of the comingday. Of course, there are many other changes before the daybreak. Themost important thing is to get up when our body is ready for the day(Illnerová, H. 2005, p. 9-10).

On the other hand, we can increase the production of melatonin byexposure to sunlight over the day. The sunlight also has positiveeffects against depression. On the other hand, absolute dark must be atnight when sleeping (Tab. 2) (Fat, P. 2008).

Response of melatonin production to wavelength light from 440 to 600 nmhas been tested with volunteers. It was found that is it necessary todecrease the light wavelength to 420 nm. Sensitivity to this wavelengthhas been tested with several volunteers placed in a dark room. Half ofthe volunteers was exposed to wavelength light of 420 nm from 2:00 till3:30, and the other half stayed in dark. First half of volunteers,exposed to light radiation, the melatonin level dropped to 76.4 or 47.6pg/ml. Second half the melatonin level ranged around 70 μg/ml. Thevolunteers who were exposed to wavelength 420 nm had melatonin leveldecreased by six orders. It was found that the most efficient range ofwavelengths for melatonin regulation is 446-477 nm (FIG. 2) (BRAINARD GC, et al.). Action Spectrum for Melatonin Regulation in Humans: Evidencefor a Novel Circadian Photoreceptor. J Neurosci. 2001, August 15;21(16):6405-12).

There are many manufacturers of LED lamps but they do not addresselimination of the blue light which effect is not healthy for a man atnight.

When assessing current light sources with some possibility to beswitched, with transition phases and the like, we can find that if sometechnical solutions have addressed “safety”, it concerned primarilyprotection of the source, of the technical system or of the property,etc. The presented concept, however, considers the “safe” mode of thelight source in a quite different and new relation of a long-term effecton human health.

Because of European effort to decrease power consumption, there is stillthe option to provide for lighting using dimmed halogen bulbs ininterior spaces and using sodium bulbs in outside spaces late eveningand at night but awareness of economy of LED sources spreads and itresults in general preference at the expense of the current sources,input of which before dimming discourages a consumer. Corruption ofcircadian rhythms and particularly of night immune and regenerativeprocesses of inhabitants and of whole ecosystems living next to humanresidences and communications have not been addressed, yet.

1) Conception—Basic Idea

In common interior and exterior illumination practice, we have beenusing artificial light sources from more than 100 years and they aretypically designed with just one mode of emitted light. However, life onearth has taken place in the natural conditions of variable illuminationcharacter for millions of years which may be also one of the fundamentalprerequisites for live nature functioning as we know it—day and nightchanging. Scientific researches of recent years show that the influenceof the so called “modern” light sources on the human population healthhas been strongly underestimated so far. Economic focus of theindustrial civilizations as a result of the mass use of light sources to“prolong the day or the time during which one can work” significantlyaffects the natural night conditions that have meant the sleep mode fora human, while this is a summary of several properties of the lightbeing used, not just a single parameter like illumination intensity etc.The presented concept brings the extension of the current light sourceswith the products working in several operating modes focused onergonomics and health impacts on the operator mainly in the areas ofaffecting the sleep mode.

2) Input Conditions and Requirements

Scientific studies prove that the creatures' organisms are accustomed toa certain course of light character changes during the day phases in thelong-term development, while the so called “biological clock” of liveorganisms and obviously a human also follow such changes to a largeextent. The light sources being so far in mass production are primarilydesigned to provide spare daylight for example in enclosed spacesor“artificial day prolongation” till evening and night hours. Such lightis suitable provided that it's used to illuminate a human activitytraditionally performed in daylight (such as work, sport, study).Obviously, it's no more fit for other phases that are typical for thecourse of the day and vital for health—these include evening relaxationphase (attenuation and natural daylight changes before the sunset) aswell as the sleep preparation phase which was accompanied in the longterm by staying in environment slightly lit by fire. The technicalspecifications provided by the scientific researches also show whichvisible spectrum bands are important for healthy and natural course ofthe above-mentioned phases of relaxations and sleep preparation:

a) critical blue band—typically 440-470 nm

-   -   causes the internal “wake-up” of organism and prevents the sleep        preparation        b) white-green band of brightness—typically 520-575 nm    -   within this band, we are most sensitive as regards the        brightness and such illumination helps us to stay in active mode        c) amber band—typically 585-610 nm    -   this is the area of light optimal for the evening relaxation        phase and this is where the“safe” band for possible sleep        preparation begins        d) red band—typically 610-700 nm    -   this is quite safe for the night sleep phase and in addition, as        the human vision brightness sensitivity starts to decrease        sharply, such illumination is virtually perceived as being just        “very weak”

SUBJECT MATTER OF THE INVENTION

A quite new lamp has been developed that concentrates on harmonisationof circadian rhythms of men and animals, thus of all beings affected bythe modern way of life concerning light pollution. It has shifted theeffect required of light to conform to the day rhythm of a man, thus ofcircadian rhythms on a day and, on the other hand, it has suppressedundesirable imbalance of these rhythms at night when we need to see andto make light.

LED lighting consists of two, at least, extreme light sources, namelyfor the day mode and for the night mode.

The night lighting mode is provided just with the red and amber lightwith parameters like a fire has, and the day mode is provided with blueLEDs covered with luminophores with parameters similar to sunlight on abright day.

The night lighting mode emits monochromatic red and amber light withwavelength about 580 to 680 nm only.

It is favourable to have the night mode light emitted from a LED chipmonochromatic with maximum at 590 nm for amber light and maximum at 628nm for red light. The unusual direct red and amber light without anyexcitation in blue wavelengths has been

used in the night mode to be completely sure that light radiation fromthese LED chips contains no blue and green light which would imbalancean organism and wake it from the night mode.

Thus, it is possible to have the LED light in the night mode for easyshort-term use, for example when one awakes and needs to go to thebathroom or for all the night when nursing a baby without the user beingharmed by feeling of sleeplessness, even in the short term.

A LED lamp is connected in such a way that the first switch alwaysstarts the night mode under the manual control. So a sleepy user neednot solve what and how to switch at night without risking being exposedto the daylight by mistake. The day lighting mode would only occurwithin further switching. Amber light is satisfactory for safenot-waking lighting but addition of red light would cause a morepleasant feeling.

The day lighting mode is provided by blue LED chips covered withluminophores emitting continuous band spectrum of visible light withwavelength 380 nm to 700 nm and chromaticity temperature CCT 3500 to4200 K, it is favourable to have the CRI 90 value or more which providesfor high fidelity of colour rendering and the light spectrum is similarto that of a bright day. Under such lighting an organism is more excitedand a brain is stimulated to higher cognitive performance. Thedifference against common bulbs is similar to light on a rainy or asunny day when a man is a bit more alert than in rain.

Thus a LED lamp consists of light emitting diodes (LED) with circadianregulable mode of radiated light providing for its health safety becauseis contains two, at least, switchable chains of LED chips. I. chain forthe night mode and III. chain for the daymode and the I. chain containsone, at least, LED chip emitting amber light in range of wavelength 580nm to 610 nm and one, at least, LED chip emitting red light in range ofwavelength 610 nm to 700 nm, III. chain contains one, at least, LED chipcovered with luminophore emitting continuous band spectrum of visiblelight of wavelength 440 nm to 700 nm and chromaticity temperature CCT3800 to 4200 K. It is favourable, if the emitted visible spectrum of theIII. chain consists of relative share of 25 to 33% of blue colour, 22 to35% of green colour and 38 to 45% of red colour.

It is favourable if a LED lamp also contains an evening lighting modewhich emits continuous band spectrum of visible light with wavelength380 nm to 750 nm and chromaticity temperature CCT 2500 to 2800 K and itis favourable if its colour rendering index CRI has value of 80, atleast.

The evening lighting mode serves for preparation for sleep and forrelaxation, the emitted light contains low share of blue colour and itis similar to day light 45 minutes before sunset.

The evening lighting mode js provided either with a II. chain of LEDchips which contains one, at least, blue LED chip covered withluminophore with chromaticity temperature of CCT 2500 to 2800 K or it ismixed through switching the I. and the III. chain together with thepossibility to apply variable intensity of each chain and continuous orgradual transition into the night lighting mode and lighting of only theI. chain. It is favourable if the gradual or continuous transitionbetween the lighting modes is provided by insertion of a dimmer betweenthe chains.

The evening lighting mode emits visible spectrum consisting of relativeshare of 7 to 19% of blue colour, 27 to 31% of green colour and 50 to65% of red colour.

The spectral maxima of light intensity according to light wavelengthwere used to determine the ratios among the represented spectrum coloursas follows: blue spectrum colour—maximum at 455 nm, green colour—maximumat 555 nm and red colour—maximum at 628 nm.

A LED chip consists of compound semiconductors. A characteristicsemiconductor applicable for a blue LED is:

a) Indium gallium nitride (InGaN) which is used for shorter wavelengths,i.e. for the light connected to daily activities and we consider thisalloy to be fully unwanted for the relaxation/sleep mode. Gallium is anecessary element for application in band about 580 nm and higher. Otherelements can be added to modify the band emitted.b) Aluminium gallium indium phosphide (AlGaInP) which occurs in theproduction of relatively widespread red-amber LED elements and meets therequirements for the “safe” band for relaxation/sleep preparationc) Gallium arsenide (GaAs) is a typical material for pure red light onthe edge of the visible spectrum, thus being quite safe even for thenight sleep mode.

Blue LEDs are coated with luminophores. It is favourable to useluminophores with commercial name ZYP630G3, emitting maximum light atwavelength of 628 nm and ZYP555G3, emitting maximum light at wavelengthof 555 nm that have been dispersed in a silicone bed that was appliedover the blue LED. The bed for the LED can be of various shape, it isfavourable to have a wall of the LED bed inclined by 20° against level.

The II. chain (evening mode) has been designed in such a way that theoutgoing light which passes from a LED through luminophore consists of30% blue, 20% green and 50% red colour of the light spectrum. The III.chain (night mode) of lighting has been designed in such a way that theoutgoing light which passes from a LED through luminophore consists of50% blue, 20% green and 30% red colour of the light spectrum.

The night mode completely eliminates light blue wavelength the action ofwhich harmuman organism at night. It is advisable to switch on thislight everywhere after 9 p.m., and to use it till sunrise. The eveningmode has blue wavelength and it is advisable to see it in the afternoonand for reading. The day mode represents the full day sunlight and itshould only be used during a day from sunrise till dark, both home andin offices, and possibly in circumstances where vigilance andperformance are required.

The manual switching of chains is set so that after lights are switchedoff and on again, first the I. chain is switched on with monochromaticamber and red colours, thus no effect on circadian rhythm and sleepquality would occur after each wake and switching light on. Theswitching works in such a way that a filtering capacitor is charged to 5V, and it starts discharging after the light is off or power supply isoff. If voltage drops under 2 V, on the next light switching-on the I.chain with monochromatic amber and red colours switches on, this occursafter some 10 seconds. If the light is switched in shorter time, thecapacitor is discharged to, say, only 4 V, the system will not switchautomatically into the I. chain but into the next chain.

Values of colour rendering index are for the II. and III. chains 80 ormore, thus they almost correspond to the natural sunlight.

A light source with switch into the “safe” light mode for an observer

a) critical blue band—typically 440-470 nm

-   -   causes the internal “wake-up” of organism and prevents the sleep        preparation        b) white-green band of brightness—typically 520-575 nm    -   within this band, we are most sensitive as regards the        brightness and such illumination helps us to stay in active mode        c) amber band—typically 585-610 nm    -   this is the area of light optimal for the evening relaxation        phase and this is where the“safe” band for possible sleep        preparation begins        d) red band—typically 610-700 nm    -   this is quite safe for the night sleep phase and in addition, as        the human vision brightness sensitivity starts to decrease        sharply, such illumination is virtually perceived as being just        “very weak”

Thus, the proposed conception of a light source assumes that at leastone of the operating modes will be quite free of energy in the criticalblue band a) or attenuated by several orders of magnitude with respectto the major band c) or d).

Switching or gradual transition to the safe mode for relaxation/sleepmay happen in several manners:

e) in automated mode

-   -   based on the coordination for example with a sensor of natural        light brightness or any sophisticated control system        f) direct switching by user    -   in this case, this concept assumes that the “safe mode” should        be the first one in which the source begins to light after being        enabled from the off state.

An inside lamp of DEN type (Day, Evening, Night)

In the time from dusk, which for example occurs in December around 4p.m., till evening, the source operates in the Day Mode and itcompletely emits short wave photons, like the sun during a day insummer. Evening, the source switches automatically or manually into theEvening Mode where it emits markedly less short

wave photons and more long wave ones which simulates a situation beforesunset. Then, at 9 p.m., thus 90 minutes before the usual time for goingto bed (when traffic drops), the DEN source switches into the NightMode, where it emits light completely without short wavelengths and thusit does not disturb the circadian rhythms. Taking into account that 65%cones in human eye catch long-wave photons, 33% cones serve to catch themedium range and only 2% cones provide for vision in the short-waverange, the switch to the long-wave light will not harm vision, theopposite is true, markedly less long-wave photons (of red and amberlight) satisfy for adequate visual orientation, than for short-wavelight (blue, green). Early morning, a LED lamp switches first in theEvening Mode and then into the Day Mode where it stays till full day.Outside Lamp

In the time from sunset till late evening a lamp operates in the DayMode and it emits high quantity of short-wave photons, like the sun insummer. Late evening it switches into the Night Mode where it emits justlong-wave light. Morning, the source switches back into the Day Mode.

It is favourable to connect the LED lamp into a block schemes in optionDEN 1-4 (Colour or CCT switching bulb/LED luminaire):

All the four options have these common parts:

front-end circuit with overvoltage protection and a rectifier bridge,constant current source with isolation transformer, output powerswitches for the channels and control circuit with circuits to switchlighting modes.

Option 1: switching between channels is performed directly by switchingoff and on in a certain sequence, the circuit selecting between lightingmodes with own supply assesses switch-off of line supply itself. Whenthe time for switch-off is exceeded the timing circuit for switchbetween lighting modes is reset.

Option 2: switching between channels is performed directly by switchingoff and on in a certain sequence, the circuit selecting between lightingmodes assesses switch-off of line supply independently. When the timefor switch-off is exceeded the timing circuit for switch betweenlighting modes is reset.

Option 3: switching between channels is performed using a controlcircuit that uses external control signals for each channel. In thiscase, reset is not necessary under standard circumstances.

Option 4: switching between channels is performed using a programmedcontrol system pre-programmed for certain light scenes or aradio-communication module transmitting control orders from a superiorsystem. In this case, reset is not necessary under standardcircumstances.

Electric Circuit of LED Lamp (Application FIG. 14):

The electric circuit of a LED lamp consists of an input protectioncircuit consisting of R1 resistor providing for overcurrent protection,varistor V1 providing for overvoltage protection, further there are arectifier bridge with filter C1 providing for supply of a current sourceconsisting of circuit U1, supplied through resistors R2 and R3 withfilter C2 and resistor R5 and diode D2 connected to winding oftransformer T1 together with parallel combination of resistors R6 andR7, further resistor R4 and C6 providing for circuit timing, outputwinding of transformer T1 is connected through diode D3 to filtrationcapacitor C3 and resistor R9 which forms operating voltage+VLED for thesections of LED lamps, and then filtration capacitor C4 is suppliedthrough resistor R8 and C5 providing for right time constant for “Option1” with parallel Zener diode D4 setting operating voltage for controlcircuit U2 controlling shine of the relevant LED group

CCT/Amber using switch transistors Q1, Q2 and Q3 where resistor R10limiting current in this circuit is connected to collector Q3.

An outside lamp is designed just of two chains. The I. chain switches onthe light with chromaticity temperature 3800-4500 K first. It is advisedto switch on this chain approximately from 4:30 p.m. to 8:00 p.m. inwinter. Within this time range, people come from work, children fromschool and traffic is often heavy, and thus it is necessary to extendday light, particularly for safety. From 8.00 p.m. the traffic is not soheavy and people are home, ready to relax and prepare for bed. In thistime the I. chain switches automatically into the III. chain whichprovides light with chromaticity temperature about 2500-2700 K. Insummer when good visibility keeps even after 7.00

p.m., it is advisable to switch on the III. chain automatically inpublic lighting e.g. from 8.00 p.m.

The source for outside lamp can be designed as follows:

White chips with luminophore, red chips and amber chips can be insertedinto a ceramic plate and it is favourable if ratio between amber and redchips is 4:5.

Automatic switch between the day and night modes which is favourable touse to outside lighting runs continuously namely in such a way thatfirst the day mode is on, thus the III. chain—blur LED with luminophore.In the moment when the modes should turn, a circuit is switched using aswitch to the I. chain and continuously current in the

III. chain decreases while current in the I. chain, thus in red andamber chips, increases to 100% using a dimmer. The full transition fromthe day mode into the night mode shall occur when the current in theIII. chain drops to 10% and the switch then disconnects it. The lightdoes not change so that there is, for example, an unwanted frighteningof a driver but the transition between chromaticity temperature 4000 Kand 2672 K is gradual, slow and it will not affect anyone knowingly.

OVERVIEW OF FIGURES

FIG. 1: Comparison of representative light sources and their spectraaccording to the state of the art: a) low pressure sodium lamp, b)monochromatic LED with semiconductor AlInGaP with wavelength 590 nm to595 nm, c) high pressure sodium lamp, d) PC amber, e) filtered warmwhite LED, f) cold white LED with chromaticity temperature of 4100 K, g)cold white LED with chromaticity temperature of 5100 K

FIG. 2: Sensitivity to light wavelength: spectre of common white LEDwith colour temperature 4800K (above). The left curve in the lowerfigure shows sensitivity of melatonin and the middle curve showssensitivity of human eye in standard day vision.

FIG. 3: Unsuitable source of light LED 3098 K—little blue wavelength forwork, too much blue wavelength for relaxation

FIG. 4: Commercial LED bulb 4034 K with low CRI value

FIG. 5: I. chain of LED lamp: amber:red 4:5

FIG. 6: I. chain of LED lamp: amber:red 6:4

FIG. 7: II. chain of LED lamp: CRI=98.3, blue 15%, green 25%, red 60%

FIG. 8: III. chain of LED lamp: CRI=98, blue 25%, green 35%, red 40%

FIG. 9: Outside lamp—III. chain

FIG. 10: Outside lamp—combination of I. and III. chain

FIG. 11: Outside lamp spectrum—I. chain, amber:red 3:7

FIG. 12: Schematic drawing of inside LED lamp with manual switch

FIG. 13: Ceramic plate with chips for an outside lamp

FIG. 14: Circuit diagram of LED lamp for DEN

FIG. 15: Circuit diagram of I. and III. chain of outside lamp

FIG. 16: Block scheme—Example 8a)

FIG. 17: Block scheme—Example 8b)

FIG. 18: Block scheme—Example 8c)

FIG. 19: Block scheme—Example 8d)

FIG. 20: Spectrum of luminophore with blue LED for 2700 K—II. chain,produced according to Example 2b).

FIG. 21: Spectrum of luminophore with blue LED for 4000 K—III. chain,produced according to Example 3b.

FIG. 22: Properties of light sources—state of the art

FIG. 23: Time schedule of lighting of public space using LED lamps

FIG. 24: Comparation of spectra of I. chain of LED lamp: amber:red 6:4,II. chain of LED lamp: CRI=98.3, blue 15%, green 25%, red 60% and III.chain of LED lamp: CRI=98, blue 25%, green 35%, red 40%

FIG. 25 Chromaticity temperature visualization

FIG. 26 Circle of melatonin during a day and night

FIG. 27 Circuit diagram of LED lamp for DEN

EXAMPLES Example 1

Production of LED Lamp for Evening Mode—2700 K

a) Semiconductor InGaN and luminophore NaLuS₂

First the luminophore was produced, it originated from Na₂CO₃ and LuO₃in a chemical reaction in H₂S atmosphere. A mixture of oxides was placedin an alumina tray into an alumina tube and the mixture was slowlyheated in an electric resistance furnace to temperature 1200° C. underargon atmosphere. Then the mixture was annealed in H₂S

atmosphere for 80 minutes and then slowly cooled approximately by 1° C.per minute. After room temperature was achieved, the resulting productwas decanted in water and then in alcohol and then stored in argonatmosphere. The formed crystals were small plates 0.3 mm thin. The smallplates were glued to a blue chip with InGaN composition. Finally, thechip covered with luminophore was coated with silicone binding agent.

b) Semiconductor ZnSe and Mixture of Luminophores ZYP555G3 and ZYP63063in Ratio 3:4

Commercial powder luminophores labelled ZYP555G3 emitting light spectrumwith maximum at 628 nm and ZYP63063 emitting maximum at 555 nm weremixed in ratio 3:4. 0.5 g of powder mixture dispersed in silicone wasapplied on a blue LED with semiconductor ZnSe, silicone served as powdercarrier. A wall of the LED bed was inclined by 20° against the level inwhich the light goes out. This way a light source with colour spectrumin ratio blue (455 nm): green (555 nm): red (628 nm) 0.55:0.58:1.10 wasproduced. The resulting radiated light from the LED had chromaticitytemperature of 2700 K.

Example 2

Production of Light Source for Night Mode DEN—4000 K

-   -   a) Semiconductor InGaN and Luminophore YAG:Ce

First, luminophore was prepared that consisted of powder oxides: Y₂O₃,α-Al₂O₃ and CeO₂ which were weighted and mixed in stoichiometric ratio(Y+Ce):Al=3:5. Ce concentration was 0.1 at. %. The mixture of oxides wasground in a ball grinder for 8 hours and then dried and sieved. Then themixture of oxides was calcited in air at 600° C. for 4 hours. Calcitedpowder was created, it was compacted to form a ceramic body withdiameter 18 mm using uniaxial press with force 5 MPa and cold isostaticpress with force 250 MPa. The body was sintered at 1700° C. for 20 hoursin vacuum atmosphere. The generated luminophore had compositionY₃AL₅O₁₂:Ce and thickness 0.2 mm. This way prepared luminophore wasglued to a blue LED chip of InGaN composition. Finally, the chip withluminophore was coated with silicone binding agent.

This way a light source with colour spectrum in ratio blue (455 nm):green (555 nm): red (628 nm) 0.5:1.0:0.65 was produced. The resultingradiated light from the LED had chromaticity temperature of 3098 K.

b) Semiconductor SiC and Mixture of Luminophores ZYP555G3 and ZYP63063in Ratio 1:2

Commercial powder luminophores labelled ZYP555G3 emitting maximum at 555nm and ZYP63063 emitting maximum at 628 nm were mixed in ratio 1:2. 0.4g of powder mixture dispersed in silicone was applied on a blue LED withsemiconductor SiC, silicone served as powder carrier. A wall of the LEDbed was inclined by 20° against the level in which the light goes out.

This way a light source with colour spectrum in ratio blue (455 nm):green (555 nm): red (628 nm) 0.8:1.0:0.75 was produced. The resultingradiated light from the LED had chromaticity temperature of 4000 K.

Example 3

Production of LED Lamp of DEN Type

a) 33 chips in three rings were positioned on a ceramic plate. 13 bluechips with composition of InGaN semiconductor coated with luminophoreaccording to Example 2a) were positioned in the outer ring. 10 bluechips with composition of InGaN semiconductor coated with luminophoreaccording to Example 1a) and 4 red chips with composition of AlGaInPsemiconductor were inserted in the middle ring. 6 amber chips withcomposition of GaAsP semiconductor were positioned in the inner ring.

b) 33 chips in three rings were positioned on a ceramic plate. 13 bluechips with composition of SiC semiconductor coated with luminophoreaccording to Example 1b) were positioned in the outer ring. 10 bluechips with composition of ZnSe semiconductor coated with luminophoreaccording to Example 2b) and 4 red chips with composition of GaPsemiconductor were inserted in the middle ring. 6 amber chips withcomposition of AlGaInP semiconductor were positioned in the inner ring.

Example 4

Using Light Source of DEN Type

a)

A LED lamp manufactured according to Example 3a) can be switched intothree chains using any switch. A switch on the lamp or a switch on awall can be used.

After the switch is on, the light of the I. chain is on and the onlyactive chips were amber and red ones and radiated monochromatic lighthad wavelength of 580 nm. Switch-over had activated the II. chain andthe only active chips were those positioned in the middle ring withluminophore according to Example 1a), and blue light was emitted and apart of light was transformed by luminophore to yellow light. Mixing ofthese colours created warm white light with wavelengths in range 380-750nm. After repeated switchover, the III. chain was activated and the onlyactive chips were those positioned in the outer ring with luminophoreaccording to Example 2a), and blue light was emitted and a part of lightwas transformed by luminophore to yellow light. Mixing of these colourscreated warm white light with wavelengths in range 380-680 nm.

Switching-off and repeated switching-on after a period exceeding 10 scaused always activation of lights of the I. chain only withmonochromatic amber and red LEDs.

-   -   I. chain—2 W, 592 nm        -   Having been switched, the bulb will light with monochromatic            amber and red, suitable for night vision which does not            disturb the circadian rhythms.    -   II. chain—5 W, 2700 K, 97 Ra, 330 lm        -   The second stroke switches on warm white colour simulating            light 45 minutes before sunset.    -   III. chain—7 W, 4000 K, 97 Ra, 490 lm        -   The third stroke switches on day white colour that has the            same parameters as mid-day sun. The day mode is suitable for            work, it keeps a man alert.            b)

A LED lamp manufactured according to Example 3b) can be switched intothree chains using any switch. A switch on the lamp or a switch on awall can be used.

After the switch is on, the light of the I. chain is on, and the onlyactive chips were red and amber ones and radiated monochromatic lighthad wavelength of 595 nm. Switch-over had activated II. chain, the onlyactive chips were those positioned in the middle ring with luminophoreaccording to Example 1b), and blue light was emitted and a part of lightwas transformed by luminophore to yellow light. Mixing of these colourscreated warm white light with wavelengths in range 380-750 nm. Afterrepeated switchover, the III. chain was activated and the only activechips were those positioned in the outer ring with luminophore accordingto Example 2b), and blue light was emitted and a part of light wastransformed by luminophore to yellow light. Mixing of these colourscreated warm white light with wavelengths in range 380-680 nm.

Switching-off and repeated switching-on after period exceeding 10 scaused always activation of lights of the I. chain only withmonochromatic red and amber LEDs.

-   -   I. chain—LED chip 2 W, 592 nm        -   Having been switched, the bulb will light with monochromatic            amber, suitable for night vision, which does not disturb the            circadian rhythms.    -   II. chain—LED chip 5 W, 2700 K, 97 Ra, 330 lm        -   The second stroke switches on warm white colour simulating            light 90 minutes before sunset    -   III. chain—LED chip 7 W, 4000 K, 97 Ra, 490 lm        -   The third stroke switches on day white colour that has the            same parameters asmid-day sun. The day mode is suitable for            work, it keeps a man alert.

Example 5

Production of Light Source for Outside Lighting

Blue LED with Luminophore+Amber+Red LED

Blue chips with luminophores were prepared according to Example 1a).Amber chips consisted of semiconductor with GaAsPN composition withratio of elements Ga:As:P:N=1:0.15:0.85:1. Red chips consisted ofsemiconductor with GaAsP composition with ratio of elementsGa:As:P=1:0.6:0.4.

Example 6 Production of LED Lamp for Outside Lighting According toExample 5

56 chips in four rings were positioned on a ceramic plate. 24 blue chipscovered with luminophore were positioned in the outer ring. 12 amberchips and 8 red chips were inserted in the next ring. 12 blue chipscovered with luminophore were positioned in the next ring and 4 amberchips were positioned in the central ring.

Example 7

Using Light Source for Outside Lamp

Blue LED s Luminophore+Amber+Red LED

A LED lamp manufactured according to Example 6 can be switched into twomodes automatically. After switch, the first mode is activated and allthe chips positioned on the ceramic plate were active. Blue light fromthe LED was emitted and a part of light was transformed by luminophoreto yellow light. Mixing of these colours produced white light withwavelengths in range 380-680 nm and chromaticity temperature of 3855 Kand CRI=82.4. Continuous regulation activated the II. chain where onlyred and amberchips were on with chromaticity temperature of 2672 K.

The LED lamp is switched automatically or manually into three or twomodes with CCT and spectral composition suitable for the correspondingpart of the day:

Mode Night, amber light not disturbing production of hormone melatonin,with markedly suppressed share of short-wave photons or completelywithout the short-wave component (provides for good sleep).

Mode Evening, warm yellow light similar to classic glow-bulb or sunbefore sunset, with small share of short-wave/blue photons (suitable forrelaxation).

Mode Day, white day light similar to sun during a day, with marked shareof short-wave photons (supports cognitive performance of brain).

In case of manually switched inside LED lamp with three lighting modes,the switch over is carried out through repeated stroke on the switch ininterval less than 10 s. Automatically switched LED lighting is suitablefor public lighting.

Example 8

Description of the Block Schemes

-   -   a) The control system switches colour and/or chromaticity        temperature CCT through detection of current loss.

First switch ON: I. chain

Switch OFF and switch ON again: II. chain Switch OFF and

switch ON again: III. chain

A big capacitor is used to keep the system in the previous state.

-   -   b) The control system switches colour and/or chromaticity        temperature CCT through detection of current loss.

First switch ON: I. chain

Switch OFF and switch ON again: II. chain Switch OFF

and switch ON again: III. chain

A big capacitor is used to keep the control circuit in the previousstate. This practice can achieve shorter time in OFF statenotwithstanding a change stored in the capacitor in an AC/DC converter.

-   -   c) The control system switches colour and/or chromaticity        temperature CCT using a control wire.

The control wire switches colour LED and/or chromaticity temperature CCTdirectly without sequencing. The control circuit carries out filteringand transmits voltage from the control wire to a LED chain.

-   -   d) The control system switches colour and/or chromaticity        temperature CCT through request to PLC (Power-line) and/or a        wireless communication module.

PLC and/or a wireless communication module switches directly between aLED colour

and/or chromaticity temperature CCT without sequencing.

Example 9

Electric Circuit of LED Lamp

a) Using NMOSFET

The source of supply voltage is connected through connection of theprotective resistor (R1) for overcurrent protection and the varistor(V1) for overvoltage protection to input of the block (1) of theconstant current source with the isolation transformer consisting of therectifying circuit (D1), and its positive voltage output is connectedwith the positive electrode to the first filtration capacitor (C1) withthe earthed negative electrode, and with the serial combinationconsisting of the resistors (R2, R3) and the second filtration capacitor(C2) earthed on its other end with its negative electrode where thecommon point of the third resistor (R3) and the positive electrode ofthe second capacitor (C2) of this serial combination is connected toinput of supply to the current source (U1) where the third input of theisolation transformer winding (T1) together with the earthed serialcombination of the sixth and seventh resistors (R6, R7) is connectedthrough the fifth resistor (R5) and the second diode (D2) in directioncathode-anode, and where the fourth input of the isolation transformer(T1) is earthed, and the earthed fourth resistor (R4) and the sixthcapacitor (C6) providing for timing are connected to the timing inputsof the current source circuit (U1), and the output of the rectifyingcircuit (D1) is connected to the first input of the isolationtransformer (T1), and its output winding is through its output (6)connected through the third diode (D3) in forward direction to thepositive electrode of the filtration third capacitor (C3) and to theninth resistor (R9) to generate output voltage (+V LED) for the sectionsof LEDs, where this voltage (+V LED) is connected to anode input of theLED chains (3), and then the output voltage (+V LED) is connected intothe block (4) of the control circuit of the channel switches, namely tothe serial combination of the eighth resistor (R8) with the parallelcombination of the filter fourth and fifth capacitors (C4, C5) todetermine the required time constant, where to this parallel combinationof the fourth and fifth capacitors (C4, C5) the Zener diode (D4) isconnected to determine operating voltage of the second control circuit(U2) implementing the block (4) of the control

circuit of the channel switches to control the LED chains (3) to changethe lighting mode where outputs from the control circuit (U2) areconnected to the LED chains (3) using NMOSFET switch elements, namelythey are connected to electrodes (G) of the switch elements (Q1 to Q3),and their terminals (D) are connected to the cathode output of the LEDchain (3) of type CCT 4000K/7 W, to the cathode output of the LED chain(3) of type CCT 2700K/5 W and through the current-limiting tenthresistor (R10) to the cathode output of the LED chain (3) of the ambertype/2 W,b) Using NPN Transistors

The source of supply voltage is connected through connection of theprotective resistor (R1) for overcurrent protection and the varistor(V1) for overvoltage protection to input of the block (1) of theconstant current source with the isolation transformer consisting of therectifying circuit (D1), and its positive voltage output is connectedwith the positive electrode to the first filtration capacitor (C1) withthe earthed negative electrode, and with the serial combinationconsisting of the resistors (R2, R3) and the second filtration capacitor(C2) earthed on its other end with its negative electrode where thecommon point of the third resistor (R3) and the positive electrode ofthe second capacitor (C2) of this serial combination is connected toinput of supply to the current source (U1) where the third input of theisolation transformer winding (T1) is connected through the fifthresistor (R5) and the second diode (D2) in direction cathode-anodetogether with the earthed serial combination of the sixth and seventhresistors (R6, R7) where the fourth input of the isolation transformer(T1) is earthed, and the earthed fourth resistor (R4) and the sixthcapacitor (C6) providing for timing are connected to the timing inputsof the current source circuit (U1), and the output of the rectifyingcircuit (D1) is connected to the first input of the isolationtransformer (T1), and its output winding is through its output (6)connected through the third diode (D3) in forward direction to thepositive electrode of the filtration third capacitor (C3) and to theninth resistor (R9) to generate output voltage (+V LED) for the sectionsof LEDs, where this voltage (+V LED) is connected to anode input of theLED chains (3), and then the output voltage (+V LED) is connected intothe block (4) of the control circuit of the channel switches, namely tothe serial combination of the eighth resistor (R8) with the parallelcombination of the filter fourth and fifth capacitors (C4, C5) todetermine the required time constant, where to this parallel combinationof the fourth

and fifth capacitors (C4, C5) the Zener diode (D4) is connected todetermine operating voltage of the second control circuit (U2)implementing the block (4) of the control circuit of the channelswitches to control the LED chains (3) to change the lighting mode whereoutputs from the control circuit (U2) are connected to the LED chains(3) using switch elements of bipolar NPN transistors, namely they areconnected to bases of the switch elements (Q1 to Q3), and theircollectors are connected to the cathode output of the LED chain (3) oftype CCT 4000K/7 W, to the cathode output of the LED chain (3) of typeCCT 2700K/5 W and through the current-limiting tenth resistor (R10) tothe cathode output of the LED chain (3) of the amber type/2 W.

Index overview:  1 input in block of constant current source  2 input inblock of power switches  3 chains  4 block of control circuit switches 5 output  6 blue LED with luminophore  7 amber LED  8 red LED  9 I.chain 10 II. chain 11 III. chain V1 varistor R1 protective resistor D1rectifying circuit D2, D3 diode D4 Zener diode C1, C2, C3, C4, C5, C6capacitor R2, R3, R5, R6, R7, R8, R9, R10 resistor U1 current source U2control circuit G electrodes T1 transformer Q1, Q2, Q3 switch elements Dterminals

APPLICATION IN INDUSTRY

A light source suitable in households and public lighting that can beswitched between three modes, where the first mode completely eliminatesblue wavelengths and does not disturb circadian rhythms in humans andanimals.

The invention claimed is:
 1. A LED lamp comprising light emitting diodes(LED) for circadian adjustable modes of radiated light, having aplurality of switchable chains of LED chips comprising a I. chain and aIII. chain, wherein the I. chain contains at least one LED chip emittingamber light in a wavelength range of 580 nm to 610 nm and at least oneLED chip emitting red light in a wavelength range of 610 nm to 700 nm,and the III. chain contains at least one blue LED chip covered withluminophores emitting a continuous band spectrum of visible light with awavelength range of 440 nm to 700 nm and a chromaticity temperaturecorrelated color temperature (CCT) of 3800 to 4200 K, the LED lampfurther comprising a block of control circuit switches configured forswitching over from one switchable chain of LED chips to a secondswitchable chain of LED chips, the plurality of switchable chains of LEDchips, wherein after the LED lamp has a first chain turned ON and theLED lamp is switched OFF of a power supply and ON again withoutexceeding a switch-off time, the first chain is tuned OFF and a secondchain is turned ON to switch between lighting modes, and when the LEDlamp is switched OFF of the power supply and a switch-off time isexceeded, a timing circuit for switching between lighting modes is resetsuch that when the LED lamp is switched ON to the power supply again, I.chain is turned ON.
 2. The LED lamp according to claim 1, wherein thecolour rendering index CRI for the III. chain has a value of 90 orhigher.
 3. The LED lamp according to claim 1, wherein the block ofcontrol circuit switches is controlled by a computer or protocol.
 4. TheLED lamp according to claim 1, comprising a II. chain having at leastone blue LED chip covered with luminophores emitting continuous bandspectrum of visible light with a wavelength range of 440 nm to 700 nm,and has a chromaticity temperature CCT range of 2500 to 2800 K.
 5. TheLED lamp according to claim 4, wherein the colour rendering index CRIfor the II. chain has a value of 80 or higher.
 6. The LED lamp accordingto claim 1, wherein the emitted visible spectrum consists of 7 to 19%blue light, 27 to 31% green light and 50 to 66% red light.
 7. The LEDlamp according to claim 6, wherein the blue spectrum colour has amaximum wavelength at 455 nm, the green colour has a maximum wavelengthat 555 nm and the red colour has a maximum wavelength at 628 nm.
 8. TheLED lamp according to claim 1, wherein the emitted visible spectrum ofthe III. chain consists of 25 to 33% blue light, 22 to 35% green lightand 38 to 45% red light.
 9. The LED lamp according to claim 1, whereinthe amber light emitting from the LED chip is monochromatic with amaximum wavelength at 590 nm and the red light emitting from the LEDchip is monochromatic with a maximum wavelength at 628 nm.
 10. The LEDlamp having light emitting diodes (LED) with circadian adjustable modeof radiated light according to claim 1, wherein the chains are switchedusing change-over switches.
 11. The LED lamp according to claim 1,wherein the block of control circuit switches comprises an input for aconstant current source providing a supply voltage to the block ofcontrol circuit switches and an isolation transformer connected to theblock (2) of control circuit switches used for changing the lightingmode.
 12. The LED lamp according to claim 11, wherein the block (4) ofcontrol circuit switches change the lighting mode by assessing the orderin which the on and off switching of the chains occurs.
 13. The LED lampaccording to claim 11, wherein the block (4) of control circuit switcheschange the lighting by detection of the switching off of the supplyvoltage.
 14. The LED lamp according to claim 11, wherein the block (4)of control circuit switches change the lighting mode with use ofexternal control signals for each LED chain (3), wherein each of theexternal control signals is connected to a control wire.
 15. The LEDlamp according to claim 11, wherein the block (4) of control circuitswitches is programmable, and change the lighting mode by means of anexternal programmable and/or communication module in communication withthe block.
 16. The LED lamp according to claim 11, wherein the supplyvoltage is 120-230 V˜/50-60 Hz.